Marine propeller shaft and key

ABSTRACT

An improved end for a tapered marine propeller shaft end and a key with lateral positioning lugs for interconnection with a companionately tapered marine propeller hub; the shaft end includes an axial keyway with a lateral shoulder defined in the surface of the shaft at the tapered end so that, when the hub of a propeller is positioned slidingly, axially into position along the shaft, the key is prohibited from axial movement beyond a predetermined optimum keying position.

llnited States Patent [191 Perini [4 1 Jan. 28, 1975 1 MARINE PROPELLER SHAFT AND KEY [76] Inventor: Anthony C. Perini, 3035 SW. 93

Place, Miami, Fla. 33165 [22] Filed: Aug. 5, 1974 21 Appl. No.: 494,704

[52] US. Cl. 403/318, 403/356 [51] Int. Cl. Fl6d 1/08 [58] Field of Search 403/355, 356, 358, 318, 403/319 [56] References Cited UNITED STATES PATENTS 58,345 9/1866 Hawkins 403/356 X 636,411 11/1899 Lovekin 403/355 1,4l8,728 6/1922 Olsen 403/318 FOREIGN PATENTS 0R APPLICATIONS 515,911 12/1920 France 403/356 Primary Examiner-Andrew V. Kundrat [5 7] ABSTRACT An improved end for a tapered marine propeller shaft end and a key with lateral positioning lugs for interconnection with a companionately tapered marine propeller hub; the shaft end includes an axial keyway with a lateral shoulder defined in the surface of the shaft at the tapered end so that, when the hub of a propeller is positioned slidingly, axially into position along the shaft, the key is prohibited from axial movement beyond a predetermined optimum keying position.

2 Claims, 5 Drawing Figures 1 MARINE PROPELLER SHAFT AND KEY FIELD OF THE INVENTION This invention relates to a tapered marine propeller shaft end and key to receive a companionately sized marine propeller hub.

BACKGROUND OF THE INVENTION In the past, as is perhaps well known, shafts tend to break in use from the stresses which are placed upon them. This causes many problems to boat owners and users. It has been found that less than optimum positionment of the key in the keyway between the shaft and propeller hub is a contributing factor to shaft breakage.

This invention has as an object the provision of an improved marine propeller shaft end and key for connecting marine propellers thereto.

More specifically, in the past, there has been a problem in that, when a marine propeller is being axially positioned on a tapered end of a marine propeller shaft, the key is apt to slide longitudinally in the keyway too far one way or the other. In so doing this causes the surfaces of the keyway in the shaft and hub and the surface of the key to become misaligned setting up a situation which, under the stress of use causes fractures and breaking of the shaft end and lost propellers, etc.

This invention has as an object the provision of a means to reduce these difficulties by prolonging shaft life which includes an axial keyway and a mating key which is provided with laterally extending positioning projections which abuttingly engage a shoulder defined at the end zone of the key slot to constrain a mating hub and shaft end to a predetermined position. The improved device effectively prevents axial movement forwardly of the key relative to the shaft beyond a predetermined and reselected position of maximum effectiveness when the tapered hub of a propeller is being mounted thereto so that, once in the correct position the hub may be secured to the shaft by conventional means, such as a nut threaded on the shaft terminal end.

In accordance with these and other objects which will become apparent hereinafter the instant invention will now be described with reference to the accompanying drawings in which:

DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view of the end of a tapered marine propeller shaft;

FIG. 2 is a side view of the marine propeller shaft end shown in FIG. 1;

FIG. 3 is a view which has been partly broken away DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings wherein like reference characters designate like or corresponding parts throughout the several views and referring particularly to FIG. 1, the numeral 12 generally designates a tapered end of a marine propeller shaft. The numeral l4 the shaft end. The shaft, it is seen includes a threaded axial terminal extension 16 which is adapted to accommodate a companionately sized keeper nut, not shown, and a hub engaging zone 18 which is tapered to match a corresponding taper of a matching'propeller hub. There is an annular groove 20 intermediate the threaded terminal extension and the tapered zone. In the surface of the end zone an axially extending keyway 22 is provided which is of a common depth along the length thereof and which is sized to receive the key 14 therein in generally sliding axial engagement. The key, it is seen is of a radial thickness such that it extends depthwise in the surface of the end a distance of about one-half the radial distance of the key and, when apropeller is installed, extends a similar distance into the keyway 23 of the hub. A lateral recess 24 is provided in the end zone of the keyway adjacent to the annular groove. This groove or lateral recess 24 is perpendicular to the longitudinally or axially extending keyway and defines a pair of shoulders 28 and 30 intermediate the groove and the shoulder surface. The key 14, it is seen includes oppositely extending positioning means in the form of projections defined by a fixed lateral pin in the end 40 thereof. The projections or lugs 42 and 44 are best seen in FIGS. 3 and 5. When a key is slidingly positioned in the axially extending groove the lugs abuttingly engage the shoulders prohibiting axial movement forward of the key relative to the shaft end when in the position shown in FIG. 5 and a hub is axially moved into position. It will be noted that the lateral projections extend from the sides of the key in the zone adjacent the end 40 and adjacent the bottom surface 46 of the key so that the effective radial dimension of the key is not reduced.

In operation, the key is positioned as shown in FIG. 3 and, thereafter, the shaft is aligned in registry with the shaft end and key and positioned as shown by the dotted lines to be secured in position by a nut. By reason of the lugs, the key does not slide axially during the propeller installation; and as a result the key is positioned such that the full torque load is directed uniformly so as not to weaken or break or fracture the shaft end. It will be noted that the end zones of the axially extending groove 50 and 52 merge and blend with the main surface of the shaft end so as not to present sharp corners and a resultant stress riser situation and also that the juncture of the shoulders with the floor 54 of the keyway Seen 56 are rounded, preferably at a radius of about 3/16 of an inch.

In a preferred embodiment, the center line of the lateral lugs are such that the distance from the end of the key to the lateral center line of the lugs is about 5/32 inch or such a dimension as is suitable to accommodate the installation of the propeller.

What is claimed is:

1. A tapered marine propeller shaft end and key in combination for receiving a companionately sized marine propeller and hub combination, said shaft and key combination comprising,

a shaft having an end including a threaded axial extension at the terminal end and an end zone tapering toward said threaded extension and an annular groove intermediate the extension and the end zone,

site sides thereof and normally in abutting relation with said shoulder to prohibit longitudinal movement of said key in the keyway when a propeller is positioned over the tapered end zone.

2. The combination as set forth in claim 1 wherein the positioning means comprises a pin passed laterally through said key a distance from the end of the key such that the end surface of the key is in a plane which is at the terminal end of the tapered end zone. 

1. A tapered marine propeller shaft end and key in combination for receiving a companionately sized marine propeller and hub combination, said shaft and key combination comprising, a shaft having an end including a threaded axial extension at the terminal end and an end zone tapering toward said threaded extension and an annular groove intermediate the extension and the end zone, an axially extending keyway in said end zone, a key sized to nest longitudinally in and to extend out of said keyway, said keyway extending depthwise in the surface of said end zone a uniform distance of about one-half the radial thickness of the key, a lateral recess in the tapered end zone perpendicular to the axial keyway defining a shoulder intermediate the annular groove and the tapered end zone, positioning means on the key and extending outwardly of the longitudinal axis of the key on opposite sides thereof and normally in abutting relation with said shoulder to prohibit longitudinal movement of said key in the keyway when a propeller is positioned over The tapered end zone.
 2. The combination as set forth in claim 1 wherein the positioning means comprises a pin passed laterally through said key a distance from the end of the key such that the end surface of the key is in a plane which is at the terminal end of the tapered end zone. 